Objectives:This study investigated the titratable acidity and erosive potential of acidic agents on the microhardness and surface micromorphology of four restorative materials.Methods:Forty-seven discs of each restorative material; metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250) and amalgam (Valiant-Ph.D.), 12 mm in diameter and 2.5 mm in thickness, were divided into four groups (5 discs/group). Specimens were then immersed for 7 days into four storage media; deionized water (control), citrate buffer solution, green mango juice and pineapple juice. Microhardness testing before and after immersions was performed. Micromorphological changes were evaluated under a scanning electron microscope (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey’s tests.Results:The Fuji II LC and the Ketac-S showed the highest reduction in microhardness (P<.05). The Valiant-Ph.D. and the Filtek Z250 showed some minor changes over the period of 7 days. The mango juice produced the greatest degradation effect (P<.05).Conclusions:This study suggested that for restorations in patients who have tooth surface loss, materials selected should be considered. In terms of materials evaluated, amalgam and resin composite are the most suitable for restorations.

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The acidic agents used in this study affected the microhardness and elemental dissolution of ceramics. The main elemental compositions of ceramics (silicon, aluminium and potassium) decreased after being immersed in acidic agents.

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This study was conducted to evaluate the titratable acidity and effect of naturally acidic agents on the surface microhardness, elemental composition, and surface morphology of fluorapatite-leucite ceramics. One hundred and ten ceramic disks (IPS d.SIGN), 12.0 mm in diameter and 2.0 mm in thickness, were fabricated. Before immersion, the baseline data of Vickers microhardness and elemental composition were recorded. Four groups were immersed in acidic agents (citrate buffer solution, green mango juice, and pineapple juice) and deionized water (control) at 37ºC for 168 hours, whereas one group was immersed in 4% acetic acid at 80ºC for 168 hours. After immersion, specimens were evaluated and data were analyzed using one-way repeated ANOVA and Tukey's test (α=0.05). Microhardness values significantly decreased after immersion (p<0.05). In terms of elemental composition, the weight percentages of silicon, potassium, aluminum, and sodium also decreased after immersion (p<0.05). Results of this study showed that fluorapatite-leucite ceramics were affected by long-term immersion in acidic agents.

This study evaluated the microhardness and elemental composition of various ceramics immersed in acidic agents. One hundred and five discs of fluorapatite-leucite (IPS d.SIGN) and fluorapatite ceramics (IPS e.max Ceram) were randomly divided into 7 groups of 15 each. Five groups were alternately immersed in acidic agents (citrate buffer solution, pineapple juice, green mango juice, cola soft drink and 4% acetic acid) for 30 min and deionized water for 5 min in 7 cycles at 37 degrees C. Two groups were continuously immersed in 4% acetic acid at 80 degrees C for 16 h and deionized water at 37 degrees C for 245 min. Vicker's microhardness and elemental composition were recorded before and after immersion. Data were analyzed using two-way repeated ANOVA and t-test at a significance level 0.05. For IPS d.SIGN, there was statistically significant difference in microhardness values between before and after immersion in the green mango, cola soft drink and 4% acetic acid for 16 h (P < 0.05). However, for IPS e.max Ceram, there was no significant difference between before and after immersion in any of the groups (P > 0.05). EDX results of both ceramics found that the elemental percentage of Na, K, Zr, Al and Si decreased after being immersed in acidic agents.

Background/purpose: The potential erosive effects of acidic foods, sour fruits, and drinks on enamel have been extensively investigated. However, their effects on fluorapatiteeleucite porcelain restorations have not been widely examined. The purpose of this study was to evaluate the ion leaching and surface roughness of porcelain immersed in acidic agents. Materials and methods: One-hundred and forty-five discs (12.0 mm in diameter and 2.0 mm thick) were made from fluorapatiteeleucite porcelain (IPS d.SIGN). Baseline data of the elemental compositions of all storage agents and the surface roughness of specimens were recorded. Four groups of discs were then immersed in acidic agents (citrate buffer solution, pineapple juice, and green mango juice) and deionized water (the control) at 37 C for 168 h. One group was immersed in 4% acetic acid at 80 C for 168 h. After immersion, the ion leaching from solutions of all specimens for each acidic agent was measured by inductively coupled plasma optical emission spectroscopy. The surface roughness was evaluated under a profilometer. Surface characteristics of specimens were examined under a scanning electron microscopy (SEM). Data were analyzed using one-way repeated analysis of variance (ANOVA) and Tukey's multiple comparisons (a Z 0.05). Results: Fluorapatiteeleucite porcelain discs exhibited significant leaching of various ions to varying degrees and increased in roughness after being immersed in acidic agents (P < 0.05). SEM photomicrographs also indicated destruction of the surface of the porcelain discs.

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